Question

The A and B antigens in humans may be found in water-soluble form in secretions, including saliva, of some individuals (Se/Se and Se/se) but not in others (se/se). The population thus contains "secretors" and "nonsecretors."...... In matings between individuals that are blood type AB and type O, both of whom are Se/se, which of the following phenotypes will be seen?
A) AB,secretor
B) AB, nonsecretor
C) B, secretor
D) B, Nonsecretor
E) A, secretor
F) A, nonsecretor
G) O, secretor
H) O, Nonsecretor

Answer 1

Answer:

C) B, secretor

D) B, Nonsecretor

E) A, secretor

F) A, nonsecretor

Explanation:

When you cross AB(codominant) with O(homozygote recessive), it will result in 50% A(IaIo) and 50% B(IaIo).

The secretor gene is dominant and both parents are a heterozygote, so the ratio of offspring genotype should be 1 : 2: 1 while the ratio of the phenotype will be 3 secretors: 1 nonsecretor.  

The possible phenotype will be:

B nonsecretor

A secretor

A nonsecretor

B secretor

B nonsecretor